Photographic products with strippable opaque layers

ABSTRACT

This application is directed to diffusion transfer photographic products especially useful as film units in film packs or the like. Essentially the photographic products presented comprise a photosensitive element which after processing can provide a useable negative which is preferably produced concurrently with the formation of a positive image pattern.

United States Patent [1 1 [111 3,881,932

Young 1 May 6, 1975 [54] PHOTOGRAPI'IIC PRODUCTS WITH 3,316,198 4/ [967Van Gorder et al 96/83 STRIPPABLE OPAQUE LAYERS 3%??333 $1393 E1" "i""a'als fii a [75] Inventor: Richard W. Young, 5 OP e Wellesley Hills,Mass. FOREIGN PATENTS OR APPLICATIONS 73 Assignee; Polaroid Col-pantie,972,050 10/1964 United Kingdom..................... 96/67 Cambridge,Mass. Primary Examiner-Norman G. Torchin [22] 1973 AssistantExaminer-Richard L. Schilling [211 App]. No: 403,037 Attorney, Agent, orFirm-Philip G. Kiely Related US. Application Data [63]Continuation-impart of Ser. No. 239,582, March 20, ABSTRACT abandonedThis application is directed to diffusion transfer photographic productsespecially useful as film units in film [52] US. 96/76 R, 96/76 packs orthe like lglz photo-graphic] prod l. I. I I l 511 int. Cl. G03c 1/48;G036 1/90; G03c 1/84 ii i ggff i fgfiggf g gfjii figgg 3 223; [58] Fieldof Search 96/29 76 84 which is preferably produced concurrently with the96/76 71 formation of a positive image pattern.

[56] References Cited 17 Claims, 3 Drawing Figures UNITED STATES PATENTS2,565,378 B/I95l Land 96/76 C PATENIEBMAY 81975 SHEH 10E 2 FIG. I

PHOTOGRAPHIC PRODUCTS WITH STRIPPABLE OPAQUE LAYERS CROSE REFERENCE TOOTHER APPLICATIONS This application Ser. No. 239.582. filed Mar. 20.1972. now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the invention This inventionrelates to diffusion transfer photography. More precisely. the inventiondisclosed herein relates to diffusion transfer photographic film unitsor products which can be developed outside of a camera after exposureand can provide a developed. usable negative concurrently with theformation of a positive transfer image pattern.

2. Description of the Prior Art The present invention is concerned withphotographic film units. particularly adapted for employment in aphotographic film pack or film magazine of the type shown in U.S. Pat.No. 3.080305, issued Mar. I2. 1963. in the name of Joel A Hamilton.comprising a container. at least one film unit mounted for exposurewithin the container and a closure element for preventing the admissionof light into the container. As disclosed in that patent. each film unitincludes. in combination. a first photosensitive element positioned forexposure within the container; a second nonphotosensitive element,preferably a print-receiving element. adapted to be superposed with thephotosensitive element during withdrawal of the film unit from thecontainer. following exposure thereof; and frangible container meansparticularly adapted to releasably retain a fluid processing compositionfor distribution between the superposed photosensitive andprintreceiving elements after photoexposure of the film unit.

In general. the film pack or container includes an exposure apertureadapted to permit exposure of the photosensitive element; a removableclosure element located across the exposure aperture; at least one filmunit; and an opening permitting withdrawal of the closure element andfilm units from the container successively through this opening. Theclosure element and each film unit includes a leader adapted to projectfrom the film pack through the opening whereby to provide means forselectively withdrawing the closure element. or a film unit. from thefilm pack into contact, and in engagement. with means adapted to provideindividual distribution of the retained fluid processing composition.between superposed photosensitive and nonphotosensitive elements.

Film packs of this type are intended to be employed in photographicapparatus, such as a camera, which include means for maintaining a filmpack in position for exposure, means for selectively exposing thephotosensitive element of successive film units of the pack. and meansfor engaging each film unit during withdrawal from the pack. afterphotoexposure. and distributing the retained processing fluid between,and in contact with. the contiguous photosensitive and print-receivingelements of the film unit. for effecting photographic diffusion transferprocessing of the respective. photoexposed film unit. Processing ofeachfilm unit may thus be effected manually by grasping a leader attached tothe film unit and withdrawing the leader and film unit from both thepack and the camera.

ln photographic diffusion transfer processing. the photosensitive sheetelement is normally first exposed and then biased into superposedrelationship with a second sheet element. which is, in general,photographically inert and aids in the controlled distribution of theprocessing composition. The photosensitive element may contain anintegral print-receiving stratum or the second sheet element maycomprise a transfer imagereceiving element. The contiguous sheetelements are moved relative to, and between. a pair of suitably opposedmembers such as gapped parallel pressure rollers or platens. Applicationof pressure to the frangible fluid-retaining means effects controlledrupture thereof and predetermined unidirectional distribution of itsprocessing composition contents between, and in contact with. theopposed surfaces of the superposed elements. After transfer processing.the image-carrying area of the printreceiving element may be separatedfrom the laminate.

As those skilled in the art know, useable. i.e.. fully developed andfixed negatives have been heretofore obtained using diffusion transferphotographic prod ucts. e.g.. film units and techniques. Detailsrelating to such products and techniques can be found. for example, inUS. Pat. No. 2.705.676. issued to Edwin H. Land and Howard G. Rogers onApr. 5. I955. and in US. Pat. No. 3.345.166. issued to Edwin H. Land.Meroe M. Morse and Elizabeth L. Yankowski on Oct. 3. I967. Also filmproducts designated as Polaroid Type 55 Film (Polaroid Corporation.Cambridge. Massachusetts) are commercially available and cansimultaneously provide useable negatives as well as positive imagepatterns. However. as those skilled in the art also know. useablenegatives have not been obtained in photographic film units of the typedescribed before. e.g.. photographic film units for use in aphotographic film pack or film magazine such as disclosed in theaforesaid US. Pat. No. 3,080,805. The present invention is particularlyaddressed to this long outstanding problem in the art and providesdistinctive film units which can provide a developed. useable negativewhich is preferably formed concurrently with the formation of a positiveimage pattern.

SUMMARY OF THE INVENTION The present invention is directed tophotographic products comprising a photosensitive element which afterprocessing. i.e.. development and fixing. and. optionally. formation ofa positive image. can provide a substantially transparent image-bearingmember and which is distinctively adhered to an opaque plastomeric sheetmaterial. Photosensitive elements of the type presented by the presentinvention are particularly useful for providing film units which can bedeveloped outside a camera and the photosensitive elements areespecially adaptable for use in film packs or magazines of the typedescribed before. Essentially. the preferred products of the presentinvention employing the novel photosensitive elements comprise first andsecond sheet elements coupled together across their leading endsections. The first sheet element comprises an opaque plastomeric sheetmaterial having an optical density of at least about 6 and preferably atleast about 9. Other essential members of the first sheet element are aphotosensitive element comprising a photosensitive layer coated on apellucid, e.g.. substantially transparent or translucent layer adheredto a surface of an opaque plastomeric sheet material. The opaqueplastomeric sheet material is distinctive in that it comprises anopacifying system. e.g.. a pigment or dye. dispersed in a polymericmatrix which can provide an effective adherent capability between thepellucid layer and the plastomeric sheet material until the sheetmaterial is contacted with a fluid. e.g.. a liquid or gas. which cancause swelling of the polymeric material of the matrix. In other words.the polymeric material provides a tight bond to the photosensitive sheetmaterial in the dry state only. Upon swelling. the polymeric material nolonger provides an adherent capability and the plastomeric sheetmaterial separates or can be separated from the photosensitive element.

The second sheet member has an opaque support and can function merely asa spreader sheet. Preferably. however, the second sheet member carrieson one surface thereof a diffusion transfer image-receiving element soarranged and positioned that the receiving element can receive adiffusion transfer image pattern from the photosensitive element whenthe first and second sheet members are placed in superposition and afluid processing composition is distributed between the photosensitiveand receiving elements.

The film units of the present invention further include a rupturablecontainer containing a processing composition. In the preferredembodiment of the present invention the rupturable container is carriedon the surface of the first sheet member between the leading edgethereof and the photosensitive element. In accordance with the mannerswell known to the art. the contents of the container are distributedbetween the photosensitive and image-receiving elements to therebyaffect processing as the film unit is passed between pressure applyingmembers.

BRIEF DESCRIPTION OF THE DRAWINGS FlG. l is a fragmentary side view of apreferred arrangement of the essential elements of the essential membersof the photosensitive elements of the present invention;

FIG. 2 is a fragmentary perspective view of a photographic film unitembodying the invention;

FIG. 3 is a front and rear plane view of the film unit of HO. 2.

DESCRIPTION OF THE PREFERRED EMBODlMENT The film units of the presentinvention are especially adaptable for use in a film pack or magazinecomprising a plurality of individual film units. Each film unit includesa photosensitive element. a second element. preferably a printreceivingelement which can be superposed with the exposed photosensitive sheetduring processing. and a rupturable container of processing fluid.Processing of the film unit is effected in the camera by a pair ofpressure-applying members. preferably rolls. which engage the film unitas the latter is withdrawn from the camera and distribute a processingfluid from the container in a layer between the photosensitive andprintreceiving elements. Each film unit includes a leader which servesas means. projecting from the camera. to be grasped for pulling the filmunit from the camera between the pressureapplying members.

Reference is initially made to FIG. I where there is shown afragmentary. cross-sectional view of the essential members ofthephotosensitive element of the present invention.

The opaque plastomeric sheet member 14 provides partial protection forthe photosensitive element 16 after the unit has been removed from thecamera and until processing is complete. Accordingly, sheet member 14preferably has an optical density of at least about 6 over the entirevisible spectrum and preferably has an optical density of at least about9. Also member 14 is a thin. substantially fluid swellable plastomericsheet material preferably having a thickness no greater than about 3mils but having sufficient strength to resist tearing and wrinklingduring the exposure. the withdrawing of the unit from the camera and thedevelopment of the film unit.

In accordance with the practice of the present invention member 14includes an opacifying system comprising a pigment or dye dispersed in apolymeric matrix having distinctive characteristics. Specifically thepolymeric material comprising the matrix is characterized in that it canprovide an effective adherent capability between sheet member l4 andbase member 18 until such time as member I4 is contacted with a fluidwhich causes the polymeric material to swell. Upon swelling. thepreexisting adherent capability is diminished to the extent that member14 can be easily removed from member 18.

The opacifying system included in member 14 canas mentionedcomprise apigment or dye dispersed in the polymeric matrix to provide an opticaldensity for the layer sufficient to prevent transmission ofsubstantially all of the light incident thereon. The preferred pigmentis carbon black but mixtures of other pigments. e.g.. titanium dioxide.iron oxides etc. can also be suitably employed. Dyes can also bedispersed in the polymeric matrix of sheet member 14 to render the sheetopaque and such dyes can be used alone or in combination with pigmentsto obtain the desired function.

The polymeric matrix of sheet member 14 comprises a polymeric materialwhich can be swollen but is not soluble to any significant degree in theparticular fluid employed to remove sheet member 14 from base member 18of photosensitive element l6. As those skilled in the art know. thedegree of swellability of a polymeric material as opposed to the degreeof solubility of the material in the fluid employed for removal willvary de pending primarily on the polymeric material(s) and/or thefluidts) employed. However. in the practice of the present invention thebalance between the swellability and solubility characteristics is suchthat the primary affect of the fluid on the polymeric material is tocause swelling of the material rather than dissolving the material toany significant extent so that sheet member 14 can be removed from basemember 18 as one piece or in large pieces rather than as flakes ordispersed particles.

Especially suitable polymeric materials useful in the practice of thepresent invention includes those which can provide thin layers of hightensile and tear strength as well as the desired degree of swellabilitydiscussed above. The desired degree of swellability can be obtained bythe selection of the proper combination of polymeric material and fluid.For example. many polymeric materials can be rendered swellable in aparticular fluid by cross linking techniques or the like. Also manypolymeric materials are known which are soluble in a fluid at onetemperature but are only swellable by the fluid at other temperatures.

In the especially preferred embodiment of the present invention a sodiumsulfite solution is employed as the fluid to remove sheet member 14 frombase member 18. Accordingly. the especially preferred polymericmaterials are those which are swellable but substan tially insoluble insodium sulfite solutions wherein the sodium sulfite can vary inconcentration. for example, from about 0.5% by weight to about 30% byweight. Suitable specific polymeric materials include partially andfully hydrolyzed polyvinyl alcohols. polyacrylamides. carboxyalkylcelluloses and the like. The following Table illustrates specificcombinations of opacifying and polymeric materials which can be coatedon a polyester base member 18 to provide suitable sheet members 14 (0.8mil thick) of the type to which the present invention pertains.

TABLE 1 Parts by Weight) l. A fully hydrolyzed. hot water-solublepolyvinyl alcohol sold by E. l. DuPont de Nemours. lnc., Wilmington.Del.

2. A partially hydrolyzed. cold water-soluble polyvinyl alcohol sold byE. l. DuPont.

3. A chemically modified. cold water soluble polyvinyl alcohol sold byBorden Chemical Co.. New York N. Y.

4. A non-ionic wetting agent sold by Rohm & Haas Corporation,Philadelphia. Pa.

5. An alkali-soluble acrylic resin sold by B. F. Goodrich. Co..Cleveland, Ohio.

6. A poly(hydroxypropyl acrylate) sold by Ram and Swanson, lnc.,Wilmington. Mass.

7. A water-soluble polyethylene glycol sold by Union CarbideCorporation. New York, N. Y.

A particularly preferred sheet member is composed of the following:

Parts by Weight Elvanol 70-05 3.3 Elvanol T-ZS" l0 Carbon black 6.6 GAFS4130 5 Voranol RN-485'" 2.8

8. A medium molecular weight. fully hydrolyzed polyvinyl alcohol sold byE. l. DuPont de Nemours. lnc.. Wilmington, Del.

9. A polyvinylpyrrolidone/vinyl acetate copolymer sold by GAF Corp. NewYork. N. Y.

10. A polyether polyol sold by the Dow Chemical Company. Midland. Mich.

From the foregoing. it will be seen that in addition to the swellablepolymeric material, the formulation may also contain various additivessuch as wetting agents. adhesion promoters. cross-linking agents andaids to release.

Substantially any fluid which will swell the polymeric materialsufficiently to provide the desired loss in adhesive capability may beemployed in the practice of the present invention. Since the preferredpolymeric materials comprise waterswellable materials. it is preferredthat water be employed as the swelling medium; more preferably. anaqueous solution of sodium sulfite. In a particularly preferredembodiment, hardeners are employed in the fluid to minimize scratchingon the reuseable negative. Similarly. organic salts may also be employedto assist in maintaining the integrity of the sepa- Glularaldehyde bistsodium bisulfite) addition product" Sodium citrate Water (15 g. I25 g.to make I liter 1 l. Prepared according to the procedure of US. Pat. No.3.232.761. issued Feb. l, 1966.

Base member I8 is adhered to opaque back coat l4 and after beingseparated from opaque layer 14 provides a pellucid support forphotosensitive layer 17. Accordingly, layer [8 can be fabricated of anymaterial which can obtain the desired function. Especially preferred arethose synthetic or naturally occurring polymeric materials which canprovide substantially transparent. flexible support members.Accordingly. layer 18 may comprise any of the various types oftransparent flexible supports. for example. polymeric films of both thesynthetic type and those derived from nautrally occurring products. etc.Especially suitable materials. however. comprise flexible transparentsynthetic polymers such as polymethacrylic acid. methyl and ethylesters; vinyl chloride polymers; polyvinyl acetals; polyamides such asnylon; polyesters such as the polymeric films derived from ethyleneglycol terepthalic acid; polymeric cellulose derivatives such ascellulose acetate. triacetate. nitrate. propionate. butyrate,acetate-butyrate, or acetate propionate; polycarbonates; polystyrenes;and the like.

It should be understood that although transparent base member I8 isshown as one layer. more than one discrete layer of different polymericmaterials can be employed to provide the assigned function of member 18.

The photosensitive layer l7 of element [6 can comprise one or more ofthe silver halides. such as photosensitive silver chloride. silveriodide. silver bromide. and preferably. mixed silver halides. such assilver chlorobromide. silver iodochloride. silver iodobromide or silveriodochlorobromide. of varying halide ratios and the silverconcentrations dispersed in a processing composition permeable bindermaterial such as gelatin and the like. Mixed silver halides comprisingsilver iodobromide and iodochlorobromide are especially preferred,particularly those comprising about l to 9% iodide by weight of silver.

The preferred silver halide type photosensitive layers employed for thefabrication of the photographic film unit. may be prepared by reacting awater-soluble silver salt such as silver nitrate with at least one watersoluble halide. such as ammonium. potassium or sodium chloride.preferably together with corresponding iodide and bromide. in an aqueoussolution of a peptizing agent such as colloidal gelatin solution;digesting the disper sion at an elevated temperature. to provideincreased crystal growth; washing the resultant dispersion to removeundesirable reaction products and residual water-soluble salts. forexample, employing the preferred gelatin matrix material. by chillingthe dispersion. noodling the set dispersion, and washing the nootileswith cold water. or. alternatively. employing any of the various flocsystems. or procedures. adapted to effect removal of undesiredcomponents. for example.

the procedures described in U.S. Pat. Nos. 2.614.928; 2.614.929;2.728.662. and the like. after ripening the dispersion at an elevatedtemperature in combination with the addition of gelatin or such otherpolymeric material as may be desired and various adjuncts. for example.chemical sensitizing agents and the like; all according to thetraditional procedures of the art. as described in Neblette. C. 8..Photography lts Materials and Processes. sixth Ed.. [962.

Optical sensitization and preferably panchromatic sensitization of theemulsions silver halide crystals may then be accomplished by contactwith optical sensitizing dye or dyes; all according to the traditionalprocedures ofthe art. or described in Hamer. F. M. The (yam'ne Dyes andRelated Compounds.

After optical sensitization. any further desired additives. such ascoating aids and the like. may be incorporated in the emulsion and themixture coated according to the conventional photographic emulsioncoating procedures known in the art.

As the binder for the photoresponsive material. the aforementionedgelatin may be. in whole or in part. replaced with some other naturaland/or synthetic processing composition permeable polymeric materialsuch as albumin; casein; or zein or resins such as cellulose derivative.as described in U.S. Pats. Nos. 2.322.085 and 2.541.474; vinyl polymericsuch as described in an extensive multiplicity of readily available U.S.and foreign patents or the photoresponsive material may be presentsubstantially free of interstitial binding agent as described in U.S.Pat. Nos. 2.945.771; 3.l45.566'. 3.142.567; Newman. Comment on Non-Gelatin Film. B. J. 0. P.. 434. Sept. l5. l96l; and Belgian Pat. Nos.642.557 and 642.558.

An especially preferred feature of photosensitive ele ment 16 of thepresent invention involves the integration of anti-light pipingcapability with the element so that such elements can be processedoutside the camera to provide transparencies having image patterns freefrom effects of any potential light piping. Light piping is a phenomenonwell known to the photographic art and usually involves light passingthrough the edges or ends of a film which is then scattered. reflectedor otherwise transmitted to portions of the photosensitive system tocause fogging thereof. In the film units of the present invention. thepotential for such fogging especially as the units are withdrawn fromthe camera is effectively eliminated by integrating an antilight pipingcapability with the photosensitive element. The anti-light pipingcapability can be included in the photosensitive system. e.e.. layer 17but in the preferred embodiment the capability comprises a layer l8having a photosensitive system 17 coated thereon and layer l8 comprisesa plastomeric sheet material having dispersed therein a pigment orchemical system which can effectively prevent light piping. The pigmentand chemical systems providing the effective anti-light pipingcapability are further characterized in that at least after processing.they do not prevent transmission of substantially all the light incidenton the layer containing the system. Accordingly, after processing. layer18 with photosensitive system [7 can be removed from plastomeric member14 to provide image bearing transparencies.

Particulate pigments are especially suitable in the practice of thepresent invention and include those that may or may not strongly absorblight but those that strongly absorb are especially preferred.Representative pigments include finely divided titanium dioxide.alumina. silica. barium sulfate and carbon with carbon blacks includinggraphite being especially preferred.

In the especially preferred embodiment of the present invention. afinely divided particulate carbon is dispersed in a substantiallytransparent plastomeric sheet material. such as polyethyleneterephthalate. The finely divided carbon may be a graphite. lamp black.bone black. furnace black. channel black or thermal black. The averageparticle diameter of such carbon blacks may. for example. range between9 millimicrons to about 500 millimicrons. as measured with an electronmicroscope. Carbon blacks having an average particle diameter belowabout lOO millimicrons are preferred.

The amount of carbon dispersed in layer 18 can vary somewhat dependingupon such factors as the species of carbon involved and the particlesize thereof. However. the best balance of desired properties isobtained by dispersing an amount of carbon sufficient to provide a layerwhich has an optical density as measured on the side of the layer at 700mp.of at least about 5.0 and preferably to about 6.0. the amount beinginsufficient to prevent transmission of substantially all of the lightincident on the surface of the layer. In a transparent layer about 4mils thick. this amount can correspond to between about It) to about 30mgms. carbon per ft. The carbon can be dispersed in the transparentlayer such as by milling together the carbon and polymeric materialcomprising the layer and sheeting out the dispersion in the form of afilm of the desired thickness.

Quite surprisingly. transparent layers comprising a dispersion of theabove described minor amount of carbon effectively prevent fogging ofthe photosensitive layer after the unit has been removed from thecamera. Equally important. the minor amount dispersed in the layer doesnot adversely diminish the transparency of the combination of layer 18and I7 but for all practical purposes. the combination of layers remainseffectively transparent and high quality reproductions of the imagepattern obtained in layer 17 can be prepared therefrom.

In accordance with the practice of the present invention. other pigmentswhich can absorb. diffuse or otherwise prevent transmission of radiationthat can fog portions of the photosensitive layer until processing iscomplete can be employed in layer 18 either alone or in combination withcarbon. The effective amount of such pigments can vary depending uponthe particular pigment and other considerations related. for example. tothe effect of the pigment on exposure time and on ultimate imagequality. For example, a substantially transparent layer having W: byweight titanium dioxide dispersed therein can be employed in thepractice of the present invention.

Also as mentioned. chemical systems can also be dispersed in plastomericmaterials to provide layer 18 having an anti-light piping capability.Such chemical systems include a reagent or reagents having thecapability of rendering the layer light absorbing before exposure. butalso having the capability of interacting with the processing fluidemployed to reduce the light absorbing characteristics of the layer.e.g.. a reagent or reagents providing the requisite absorptiveprotection at a first pH but which are substantially transparent at asecond pH supplied by the processing fluid. Also the reagent or reagentsare those that can interact with diffusion transfer image processingcomposition to be "discharged" so that layers containing the products ofthe interaction are rendered effectively transparent. and hence do notinterfere with viewing of the negative image pattern.

Particular reagents especially suitable in the practice of the presentinvention are dyes known to the art as "antihalation dyes." Such dyescan be readily dispersed in a plastomeric matrix to provide sheets orlayers initially having the light absorption capability of theaforementioned characteristics. Alternatively. dispersions of such dyescan be coated on other layers of the photographic product to providesuitable auxiliary protective layers. In addition to providing layersthat are initially light absorbing. the antihalation dyes can interactwith diffusion transfer image processing compositions so that thediffusion transfer image pattern can be viewed in or through layerscontaining the products of the interaction.

As mentioned. antihalation dyes are known to the art. They aredescribed, for example. in U.S. Pat. Nos. 3.47 l .293; 3.469.985;3.440.05 l; 3.389.994; 3.384.487; 3.364.029; 3.352.680. 3.340.062; and3.005.7l l and in British Pat. No. 515.998. all of which areincorporated herein by reference. Particularly preferred are thoseanti-halation dyes which can provide the desired absorption capabilityinitially, but which interact with the processing composition at a rapidrate so that the absorption capability initially present is clearedquickly from the dye-containing layer. Triarylmethane dyes. for example.are especially suitable in the present invention.

Representative dyes suitable in the practice of the present inventioninclude the following. among others:

0 Ha).-N sot-Go in (Color Index 42040) -l. S ()aNa (Color Index 42500)(Color Index 42585) The amount of dye or dyes required to provide aneffective anti-light piping capability can vary depending upon theparticular dye or combination thereof employed. However. the bestbalance of desired properties is obtained when the amount employed issufficient to provide a layer which initially has an optical density-asmeasured on the side of the layer at 700 m}l-Of at least about 5.0 andpreferably 6.0. ln most instances. the amount of dye required to providethe desired optical density is extremely low with respect to the matrixmaterial of the film containing the dye. For example. with certain dyesor combinations thereof suitable protective films can be obtained byemploying 2 milligrams of dye per 5 grams of polymer.

Reference is now made to FIGS. 1 through 3 of the drawings wherein thereare illustrated film units of the present invention which can beemployed in photographic products of U.S. Pat. No. 3.080.805. Each filmunit designated 10 comprises a first sheet element 12 and a second sheetelement [3. First sheet element 12 has as essential elements thereofphotosensitive element 16 which comprises an opaque sheet material 14adhered to base layer 18 which, as mentioned. prefera bly provides ananti-light piping capability for photosensitive system 17. Second sheetelement 13 has a support which is opaque to activating radiation forphotosensitive element l6 and can merely serve to aid in thedistribution of a processing fluid in contact with layer l7 containingthe photosensitive system. However, in the preferred film units, secondsheet element 13 comprises a diffusion transfer image receiving stratumarranged on element 13 so that said stratum can receive a diffusiontransfer image pattern when elements [2 and 13 are in superposition.

First sheet element 12 has a leading end [9 which is approximately equalin width to photosensitive element 16 and provides means for mounting arupturable container containing processing fluid. Leading end section 19is securely adhered to surface 17 of element 16 between trailing edge 33of end section 19 and leading edge 62 of element 16 and sheet material14 and also includes a tapered end section 21. First sheet element [2further includes a trailing end section 27 preferably attached to thesurface of photosensitive layer 17 of element l6 in the manner shown indetail in the front and rear views of P10. 3.

Second sheet element [3 functions as a carrier sheet for image receivingelement 22 which is approximately equivalent in width to second sheetelement 13. Element 13 further has a rectangular opening 23 whichprovides a border about image receiving element 14 which border definesthe area of receiving element 22 in which image formation can occur.Side guards 24 are secured to the side edges of second sheet element 13providing the boundary about opening 23 to provide means to facilitateretention of the processing fluid between photosensitive element 16 andimage receiving element 22 when these elements are in superposition.

Second sheet element [3 also includes a leading edge portion 25 having atapered end portion 26 similar to tapered end portion 21. The taperedend sections, e.g., 21 and 26, are secured together to define theleading end section ofthe film unit 10 to be advanced between pressureapplying members.

The length of sheet elements 12 and 13 is substantially equal and byvirture of this arrangement, the sheets are readily superposed inregistered relation during the processing of the film unit. Trailing endsection 27 of sheet element 12 extends beyond the trailing edge ofphotosensitive element 16 to coact with trailing end section 28 of sheet13 to trap any excess processing fluid which may be carried beyond thetrailing ends ot the photosensitive element 16 during distribution oftheprocessing fluid. Distribution of the processing fluid, as noted, iseffected by advancing sheet elements 12 and 13 and container 20 ofprecessing fluid. while elements 12 and 13 are in superposition betweenpressureapplying members. The pressure-applying members, e.g., opposedrolls, apply compressive pressure to the sheets progressively, beginningin the area of the container, to eject the fluid contents of thecontainer between and in contact with the opposed surfaces of thephotosensitive element 16 and receiving element 22. To aid in trappingof excess fluid, spacing members 29 may be provided on trailing endsection 28 adjacent the margins thereof for spacing apart thepressure-applying members to provide a gap between trailing end section27 and trailing end section 28 in which any excess processing fluid maybe collected and retained.

Upon superpositioning of elements 16 and receiving element 22, theintegrity ofthe so formed laminate may be maintained during processingby mechanical means such as, for example, a plurality of polymerichooks. e.g., nylon hooks, appropriately positioned on one contactsurface and a plurality of filamentary loops on the second contactsurface, such as the closure materials sold by Velcor Corporation.Manchester. N. H. Also, a continuous or discontinuous adhesive layer orlayers can be employed to form a seal between elements 16 and 22 tothereby facilitate processing external the camera in the presence ofactivating radiation. Such adhesive means may comprise a commercialpressure-sensitive adhesive such as that sold by the National CashRegister Co., Dayton. Ohio, under the trade designation P0lB-l0l as apressure activated capsular adhesive, and the like, so employed that theelements may be readily separated upon completion of processing byapplication of minimal force to the respective components.

The rupturablc container can be of the type shown and described in USPat. Nos. 2,543,l8l; 2,634,886; 2,653,732; 2,674,532; 2,702,146;2,723,051; 2,750,075, 3,056,491", and 3,056,492, and can comprise arectangular blank of fluidand air-impervious sheet material foldedlongitudinally upon itself to form two walls which are sealed to oneanother along the longitudinal and end margins to form a cavity in whichthe processing fluid is contained. Longitudinal marginal seal 32 is madeweaker than the end seal so as to become unsealed in response tohydraulic pressure generated within the fluid contents of the containerby the application of compressive pressure to the walls of thecontainer. Container 20 is mounted on opaque sheet 12 with thelongitudinal marginal seal directed toward the trailing edge 33 of endsection 19. Bib sheet 34 is secured to opaque sheet 12 and at edge 38 oncontainer 20, and facilitates restricted unidirectional flow of fluidcontents of container 20 after rupture thereof. Edge 40 of bib sheet 34terminates short of trailing edge 33 of end section 19 so that the flowof fluid contents from container 20 is directed to and distributed overlayer 17 of element 16.

For details concerning the composition of the processing fluid,reference may be had to aforementioned US. Pat. Nos. 2,705,676 and3,34S.l66.

As was mentioned, film units of the present invention are particularlyuseful as assemblage units of photographic film packs. The manners andmethods for integrating the present film units in such film packs aswell as the apparatus and structural elements involved are all set forthin the aforesaid U.S. Pat. No. 3,080,805 which is expressly incorporatedherein by reference. Essentially a plurality of such film units areincluded in the pack which is designed to be accommodated within acamera so that the photosensitive surface 17 of first sheet member 12 ofeach film unit can be exposed to an image pattern of activatingradiation. After exposure, the film unit is withdrawn from the exposurestation and film pack in a fashion so that photosensitive layer 17 andimage receiving layer 22 are in a superposed relationship and theprocessing composition of container 20 can be distributed between theselayers.

Tab 40 provides convenient means for withdrawing each unit from thepack.

After' removal of the film unit from the camera and formation of asilver transfer image. a high quality usable negative is obtained byseparating opaque sheet l4 and photosensitive element 16 from leadingend section 19 of element l2 such as by tearing sheet 14 with element 16from end section 19. After separation from end section 19, sheet 14 andelement 16 are contacted with a fluid which can cause the polymericmatrix of sheet [4 to swell so that sheet 14 can be removed as from basemember 18. In the preferred embodiment of the present invention sheet I4is removed as a single piece and removal is complete within about aminute or less. Since sheet 14 is not soluble to any appreciable extentin the removal fluid employed the sheet can be removed from the fluidwithout contamination of the fluid by the matrix material of sheet 14.This feature is important when the removal fluid also contains otheringredients which can fix or harden or otherwise treat the emulsionsurface of member 16.

A positive diffusion transfer image pattern containing element can beobtained by separating receiving element 22 from second sheet member 13in the manner shown in the rear view of FIG. 3.

As can be appreciated from the foregoing detailed description. theessence of the invention resides in the novel photosensitive elementspresented which comprise an opaque plastomeric sheet material releasablyadhered to a photosensitive system preferably integrated with adistinctive anti-light piping capability which can provide-afterprocessing and removal from the opaque plastomeric sheet material-asubstantially transparent image-bearing member useful in providing highquality reproductions. Accordingly. the novel photosensitive elementsare especially useful in diffusion transfer photographic productsparticularly those described in the above detailed description of thepreferred embodiment. However. since certain changes can be made in theabove disclosed products without departing from the spirit and scope ofthe essence of the invention. it is intended that all matter containedin the above description or shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

What is claimed is:

l. A photosensitive element which comprises a photosensitive silverhalide layer coated on a pellucid plastomeric layer and an opaqueplastomeric sheet material having an optical density of at least about6.0 adhered to said plastomeric layer on the said opposite said silverhalide layer, said sheet material comprising a substantiallywater-insoluble fluid swellable polymeric material adapted to loseadhesive capability upon swelling. thereby separating from said pellucidlayer.

2. A photosensitive element of claim I which includes a pigment orchemical system which can (1) provide an effective anti-light pipingcapability for said photosensitive element and (2) which at least afterprocessing of said photosensitive system after exposure thereof canprovide a layer which can transmit substantially all of the lightincident on the surface of said layer; and an opaque plastomeric sheetmaterial having an optical density of at least about 6.0 strippablyadhered to said plastomeric layer.

3. A photosensitive element of claim I wherein said photosensitivesilver halide layer is coated on a plastomeric layer comprising anantihalation dye which can initially provide an effective anti-lightpiping capability for said photosensitive element but which caninterreact with a processing fluid applied to said photosensitiveelement after exposure thereof to provide a layer which can transmitsubstantially all of the light incident on the surface of said layer.

4. A photosensitive element of claim I wherein said photosensitivesilver halide is coated on a plastomeric layer comprising a pigment inan amount sufficient to provide an effective anti-light pipingcapability for said photosensitive element but insufficient to preventtransmission of substantially all of the light incident on said layer.

5. A photosensitive element of claim I wherein said opaque plastomericsheet material comprises a polymeric material chosen from the groupconsisting of polyvinyl alcohol. polyacrylamides. carboxyalkycellulosesand mixtures of these.

6. A photosensitive element of claim 5 wherein said opaque plastomericsheet material comprises a carbon black as the opacifying material.

7. A photosensitive element of claim 1 wherein said photosensitivesystem is coated on a plastomeric layer having a carbon black dispersedtherein in an amount sufficient to provide an optical density for saidlayer as measured on a side thereof of at least about 5.0.

8. A photosensitive element which comprises a photosensitive silverhalide system coated on a substantially transparent plastomeric layerhaving a carbon black dispersed therein in an amount sufficient toprovide an optical density for said layer as measured on a side thereofat least about 5.0 and an opaque plastomeric sheet coated on the side ofsaid transparent plastomeric sheet opposite said photosensitive silverhalide system. said sheet having an optical density of at least about6.0. said sheet material comprising a substantially water-insolublefluid swellable polymeric material adapted to lose adhesive capabilityupon swelling. thereby separating from said transparent plastomericlayer.

9. A photographic product which can be developed outside a camera afterexposure of the product and adapted to provide a substantiallytransparent image bearing element after said product is processed bypassage between pressure applying members. said product comprising firstand second opaque sheet elements coupled across their leading endsections. said first member comprising in order. a silver halidephotosensitive layer coated on a pellucid plastomeric layer and anopaque plastomeric sheet material having an optical density of at leastabout 6.0 adhered to said pellucid plastomeric layer said sheet materialcomprising a substantially water-insoluble. fluid swellable polymericmaterial adapted to lose adhesive capabiltiy upon swelling. therebyseparating from said pellucid layer; said second sheet elementcomprising an opaque sheet adapted to be superposed said first sheetelement after exposure of said photosensitive layer as said product iswithdrawn from a camera and a rupturable container retaining processingcomposition arranged in relation with said first and second elements todistribute processing composition between said photosensitive system andsaid superposed element as said product is passed betweenpressure-applying members.

10. A product of claim 9 which includes a pigment or chemical systemwhich can l provide an effective an- 1 5 ti-light piping capability forsaid photosensitive layer and (2) which at least after processing ofsaid photosensitive layer after exposure thereof can provide a layerwhich can transmit substantially all of the light in cident on thesurface of said layer.

1]. A photographic product of claim 9 wherein said second elementfurther includes an image receiving stratum which can receive adiffusion transfer image pattern from said photosensitive layer whensaid elements are brought into superposition.

[2. A photographic product of claim ll wherein said pellucid plastomericlayer comprising an antihalation dye which can initially provide aneffective anti-light piping capability for said photosensitive layer butwhich can interreact with said processing fluid applied to saidphotosensitive layer after exposure thereof to provide a layer which cantransmit substantially all of the light incident on the surface of saidlayer.

13. A photographic product of claim ll wherein said photosensitive layerincludes a pigment in an amount sufficient to provide an effectiveanti-light piping capa bility for said photosensitive layer butinsufficient to prevent transmission of substantially all of the lightincident on said layer.

l4. A photographic product of claim 11 wherein said pellucid plastomericlayer includes a carbon black dispersed therein in an amount sufficientto provide an optical density for said layer as measured on a sidethereof of at least about 5.0.

IS. A photographic product of claim 11 wherein said opaque plastomericsheet material is selected from the group consisting of polyvinylalcohol, polyacrylamides. carboxyalkyl celluloses and mixtures of thesev

1. A PHOTOSENSITIVE ELEMENT WHICH COMPRISES A PHOTOSENSITIVE SILVERHALIDE LAYER COATED ON A PELLUCID PLASTOMERIC LAYER AND AN OPAQUEPLASTOMERIC SHEET MATERIAL HAVING AN OPTICAL DENSITY OF AT LEAST ABOUT6.0 ADHERED TO SAID PLASTOMERIC LAYER ON THE SAID OPPOSITE SAID SILVERHALIDE LAYER, SAID SHEET MATERIAL COMPRISING A SUBSTANTIALLYWATER-INSOLUBLE FLUID SWELLABLE POLYMERIC MATERIAL ADAPTED TO LOSEADHESIVE CAPABILITY UPON SWELLING THEREBY SEPARATING FROM SAID PELLUCIDLAYER.
 2. A photosensitive element of claim 1 which includes a pigmentor chemical system which can (1) provide an effective anti-light pipingcapability for said photosensitive element and (2) which at least afterprocessing of said photosensitive system after exposure thereof canprovide a layer which can transmit substantially all of the lightincident on the surface of said layer; and an opaque plastomeric sheetmaterial having an optical density of at least about 6.0 strippablyadhered to said plastomeric layer.
 3. A photosensitive element of claim1 wherein said photosensitive silver halide layer is coated on aplastomeric layer comprising an antihalation dye which can initiallyprovide an effective anti-light piping capability for saidphotosensitive element but which can interreact with a processing fluidapplied to said photosensitive element after exposure thereof to providea layer which can transmit substantially all of the light incident onthe surface of said layer.
 4. A photosensitive element of claim 1wherein said photosensitive silver halide is coated on a plastomericlayer comprising a pigment in an amount sufficient to provide aneffective anti-light piping capability for said photosensitive elementbut insufficient to prevent transmission of substantially all of thelight incident on said layer.
 5. A photosensitive element of claim 1wherein said opaque plastomeric sheet material comprises a polymericmaterial chosen from the group consisting of polyvinyl alcohol,polyacrylamides, carboxyalkycelluloses and mixtures of these.
 6. Aphotosensitive element of claim 5 wherein said opaque plastomeric sheetmaterial comprises a carbon black as the opacifying material.
 7. Aphotosensitive element of claim 1 wherein said photosensitive system iscoated on a plastomeric layer having a carbon black dispersed therein inan amount sufficient to provide an optical density for said layer asmeasured on a side thereof of at least about 5.0.
 8. A photosensitiveelement which comprises a photosensitive silver halide system coated ona substantially transparent plastomeric layer having a carbon blackdispersed therein in an amount sufficient to provide an optical densityfor said layer as measured on a side thereof at least about 5.0 and anopaque plastomeric sheet coated on the side of said transparentplastomeric sheet opposite said photosensitive silver halide system,said sheet having an optical density of at least about 6.0, said sheetmaterial comprising a substantially water-insoluble fluid swellablepolymeric material adapted to lose adhesive capability upon swelling,thereby separating from said transparent plastomeric layer.
 9. Aphotographic product which can be developed outside a camera afterexposure of the product and adapted to provide a substantiallytransparent image bearing element after said product is processed bypassage between pressure applying members, said product comprising firstand second opaque sheet elements coupled across their leading endsections, said first member comprising in order, a silver halidephotosensitive layer coated on a pellucid plastomeric layer and anopaque plastomeric sheet material having an optical density of at leastabout 6.0 adhered to said pellucid plastomeric layer said sheet materialcomprising a substantially water-insoluble, fluid swellable polymericmaterial adapted to lose adhesive capabiltiy upon swelling, therebyseparating from said pellucid layer; said second sheet elementcomprising an opaque sheet adapted to be superposed said first sheetelement after exposure of said photosensitive layer as said product iswithdrawn from a camera and a rupturable container retaining processingcomposition arranged in relation with said first and second elements todistribute processing composition between said photosensitive system andsaid superposed element as said product is passed betweenpressure-applying members.
 10. A product of claim 9 which includes apigment or chemical system which can (1) provide an effective anti-lightpiping capability for said photosensitive layer and (2) which at leastafter processing of said photosensitive layer after exposure thereof canprovide a layer which can transmit substantially all of the lightincident on the surface of said layer.
 11. A photographic product ofclaim 9 wherein said second element further includes an image receivingstratum which can receive a diffusion transfer image pattern from saidphotosensitive layer when said elements are brought into superposition.12. A photographic product of claim 11 wherein said pellucid plastomericlayer comprising an antihalation dye which can initially provide aneffective anti-light piping capability for said photosensitive layer butwhich can interreact with said processing fluid applied to saidphotosensitive layer after exposure thereof to provide a layer which cantransmit substantially all of the light incident on the surface of saidlayer.
 13. A photographic product of claim 11 wherein saidphotosensitive layer includes a pigment in an amount sufficient toprovide an effective anti-light piping capability for saidphotosensitive layer but insufficient to prevent transmission ofsubstantially all of the light incident on said layer.
 14. Aphotographic product of claim 11 wherein said pellucid plastomeric layerincludes a carbon black dispersed therein in an amount sufficient toprovide an optical density for said layer as measured on a side thereofof at least about 5.0.
 15. A photographic product of claim 11 whereinsaid opaque plastomeric sheet material is selected from the groupconsisting of polyvinyl alcohol, polyacrylamides, carboxyalkylcelluloses and mixtures of these.
 16. A photographic product of claim 11wherein said opaque plastomeric sheet material comprises a carbon blackas the opacifying material.
 17. A photographic product of claim 10 whichcomprises a photosensitive silver halide system coated on asubstantially transparent plastomeric lAyer having a carbon blackdispersed therein in an amount sufficient to provide an optical densityfor said layer as measured on a side thereof of at least about 5.0 andan opaque plastomeric sheet having an optical density of at least about6.0 adhered to said layer, said sheet material comprising a polyvinylalcohol.